AQ Group delivers award-winning extensions, loft conversions and full renovations across London, Cambridge, Oxford, Herefordshire and the Home Counties — on time, on budget, built to last.
Single and double storey rear extensions that open your ground floor to light and space — from kitchen-diners to open-plan family rooms.
Transform your unused loft into a stunning master suite, home office or guest room. Velux, dormer, hip-to-gable and full mansard — all in-house.
Unlock the hidden potential beneath your home. Full excavation, structural waterproofing and luxury fit-out — home cinemas, gyms, bedrooms and more.
Reclaim the narrow passage beside your Victorian terrace. Side returns dramatically widen your kitchen and flood the space with natural light.
Complete kitchen transformations from layout redesign and structural wall removal to full supply and installation of fitted kitchens in any specification.
Luxury bathroom renovations, en-suite installations and wet rooms. Full supply and fit including tiling, sanitaryware and underfloor heating.
Complete property transformations — structural changes, layout reconfigurations, full fit-out. One team, one contract, zero headaches.
Contemporary glass extensions that connect your home to the garden. From aluminium conservatories to bespoke brick orangeries with roof lanterns.
Use our London extension cost calculator to get a realistic price range in under 60 seconds. Select your type, size and specification for a full cost breakdown.
We visit your home, understand your vision and discuss options at no cost or obligation whatsoever.
A comprehensive fixed-price quote with full scope and timeline, delivered within 5 working days.
We handle planning permission, architect drawings and building regulations on your behalf.
Your project built by our directly employed team — on time and to the very highest standard.
"AQ Group transformed our Victorian terrace with a stunning rear extension and side return. The project took 14 weeks — exactly as promised. Exceptional craftsmanship throughout."
"Our loft dormer conversion has completely changed how we live. Beautiful finish, no mess left behind, and their project manager kept us updated every single day."
"From the first survey to final walkthrough, AQ were professional, transparent and genuinely skilled. Our basement conversion is now our favourite room in the house."
All prices include labour, materials, project management and site clearance. Planning fees and building regulations quoted separately.
Book a free, no-obligation site survey. We visit your home, listen to your vision and present honest options with no pressure.
From planning permission to final paint, AQ Group manages your entire project in-house — no subcontractors, no hidden costs, no surprises.
The most transformative change you can make to a London home. A rear extension opens your ground floor to light and space, creating the kitchen-diner or open-plan family room your family deserves. We handle every stage in-house, from the first structural calculations to the final coat of paint.
Transform dead space above your head into one of the most desirable rooms in your home. A well-executed loft conversion adds 20–25% to your property value and provides a completely private retreat for the whole family.
Perfect for Victorian and Edwardian terraces, side return extensions reclaim the narrow passage running alongside your home to dramatically widen your kitchen and flood the space with light from a glazed or lantern roof.
Where upward and outward expansion is not possible, going below ground is your answer. We excavate and convert basements into luxurious living spaces — from home cinemas and gyms to additional bedrooms with full natural light.
When a property needs everything, AQ Group takes it from shell to spectacular. We manage structural changes, layout reconfigurations and high-end fit-out as a single seamless project with one point of contact throughout.
Beautifully designed glass extensions that create a seamless connection between your home and garden. From sleek aluminium conservatories to traditional brick orangeries with dramatic roof lanterns that fill every corner with natural light.
Complete kitchen transformations managed entirely in-house. Structural wall removals, full electrical rewire, plumbing reconfiguration and fitted kitchen supply from standard to fully bespoke. Often combined with rear or side return extensions for the ultimate open-plan kitchen-diner.
From complete bathroom refurbishments to brand-new en-suite installations in loft conversions, AQ Group manages every detail: full strip-out, waterproofing, plumbing, tiling, sanitaryware supply and underfloor heating. Your bathroom transformed in 2–8 weeks.
Book a free consultation. We visit your home, understand your goals and recommend the best solution for your property and budget — no pressure, no hard sell.
Get a realistic, detailed estimate for your extension in under 60 seconds. Uses current 2026 market rates for London, Cambridge, Oxford and surrounding areas.
This estimate is a guide based on current regional market rates. Actual cost depends on site conditions, access and detailed design. A free survey gives you an accurate fixed price.
From side returns in London to full basement conversions in Cambridge and loft conversions across Oxford and Herefordshire — every project delivers flawless results.
Rear Extensions
Loft Conversions
Kitchen Renovations
Bathroom & En-Suites
Full Renovations
Ready to add your home to our portfolio? Book a free survey and let's talk about what's possible for your property.
Founded in London with a commitment to honest pricing, clean sites and craftsmanship that stands the test of time. Now serving clients across London, Cambridge, Oxford, Herefordshire and the Home Counties.
AQ Group was founded in 2009 with a single belief: that homeowners deserved a construction company that treated their home with the same care they did. From our London roots, we now complete projects across Cambridge, Oxford, Herefordshire and the Home Counties.
What sets us apart is not just our craftsmanship — it is our honesty. We give you a fixed price and we stick to it. We give you a timeline and we hit it. Our project managers keep you informed every step of the way, and our team treats your home like their own.
We are CIS registered, carry £10 million public liability insurance, and every project is backed by a 10-year structural warranty. Based in London, we serve clients across Cambridge, Oxford, Herefordshire and all Home Counties.
Every measurement, every joint, every finish. We take pride in the details that most people never see — because we know they make all the difference.
We say what we mean and mean what we say. Fixed prices, honest timelines, clear communication. If something changes, you will know immediately — not at the end.
We stand behind our work for ten years. If anything structural fails due to our work, we come back and fix it. No arguments, no delays, no questions asked.
Your home is your sanctuary. We work quietly, we clean up daily, we protect what matters to you. Living through a build is hard enough without contractors making it worse.
Time is money, and it is yours. We build at pace without cutting corners — because the faster you have your new space, the sooner your life improves.
We specify energy-efficient insulation, responsible sourcing and waste reduction on every project — because building better means building greener.
Book your free site survey and discover what AQ Group can do for your home.
Book a free, no-obligation site survey and receive a detailed fixed-price quote within 5 working days. No pressure, no hard sell.
Tell us about your project and we will arrange a free site survey at a time that suits you. No obligation, no pressure, no hard sell.
Your details are never shared. We reply within 2 hours.
Single and double storey rear extensions are the most powerful way to add space and value to a London home. AQ Group delivers stunning open-plan spaces, kitchen-diners and family rooms built to the highest standards.
A rear extension is the single most transformative change you can make to your home. By pushing your ground floor out into the garden, we create space that fundamentally changes how you live — open-plan kitchen-diners, light-filled family rooms, seamless indoor-outdoor living.
AQ Group manages every stage in-house: structural calculations, architectural drawings, planning applications, groundworks, structural frame, glazing, fit-out and decoration. A single point of contact from survey to sign-off means nothing falls through the gaps.
We work across London, Cambridge, Oxford and the Home Counties. Whether you want a modest 15m² kitchen extension or a sweeping 70m² double storey addition, our team has delivered it before — and we can show you the results.
Real projects delivered across London, Cambridge, Oxford and the Home Counties.
A clear, managed process from first conversation to final sign-off. No surprises, no delays.
We visit your home, measure the space and discuss your vision. We advise on planning, structural requirements and realistic costs — all free of charge.
Our architects produce full drawings. We submit planning applications or confirm permitted development rights and obtain building regulations approval.
Our directly employed team excavates, lays foundations, builds the structural frame and installs the roof — weathertight within weeks.
Internal plastering, flooring, electrics, plumbing and decoration complete. A full snagging inspection before your walkthrough.
All prices include labour, materials, project management, site clearance and building regulations. VAT and planning fees quoted separately.
Everything you need to know before you start. Still have questions? Call us for free advice.
Book a free site survey. We visit your home, assess what’s possible and deliver a fixed-price quote within 5 working days.
A loft conversion is the most cost-effective way to add a bedroom, home office or master suite without touching your garden. AQ Group delivers dormer, hip-to-gable, Velux and mansard conversions to the highest London standards.
The space above your ceiling is one of the most underused assets in any British home. A properly designed loft conversion can add a bedroom, en-suite bathroom, home office or private living room — all without a planning battle or the loss of your garden.
AQ Group offers every type of loft conversion: Velux (roof windows only, minimum disruption), dormer (the most popular — adds a vertical wall and full headroom), hip-to-gable (for semi-detached and detached homes), and full mansard (maximum space, requires planning). Our structural engineers design the floor strengthening and staircase as part of the build.
We serve homeowners across London, Cambridge, Oxford and Herefordshire. Each conversion includes full building regulations approval, a staircase designed for your home and a complete fit-out to your specification — from student lets to luxury master retreats.
Real projects delivered across London, Cambridge, Oxford and the Home Counties.
A clear, managed process from first conversation to final sign-off. No surprises, no delays.
We measure your loft, assess head height (minimum 2.2m required at the ridge) and confirm which conversion type suits your roof structure, budget and local planning rules.
Structural engineer designs the floor strengthening and staircase. Architect produces drawings. We submit for building regulations approval — planning only needed for mansard or hip-to-gable.
Roof alterations, dormer frame, floor strengthening and staircase installation are completed. The space is weathertight and ready for fit-out typically within 4–6 weeks.
Plasterboarding, insulation, electrical and plumbing installation, flooring, decoration and any bathroom fit-out. Handed over with full building regulations completion certificate.
All prices include labour, materials, project management, site clearance and building regulations. VAT and planning fees quoted separately.
Everything you need to know before you start. Still have questions? Call us for free advice.
Book a free site survey. We visit your home, assess what’s possible and deliver a fixed-price quote within 5 working days.
When you cannot build up or out, go down. AQ Group specialises in full basement excavations and conversions — from home cinemas and gyms to additional bedrooms and wine cellars — with structural waterproofing that lasts a lifetime.
Basement conversions are among the most complex and rewarding projects we undertake. They require deep structural expertise — underpinning, excavation, temporary works and structural waterproofing — and AQ Group has the in-house engineers and directly employed tradespeople to deliver them safely and on budget.
We offer two main approaches: conversion of an existing cellar or basement (faster and less expensive) and full dig-down excavation beneath a property with no existing basement (more complex, often requiring underpinning). Both require building regulations approval, structural engineer sign-off and specialist waterproofing.
Our waterproofing systems carry a 10-year warranty backed by a specialist insurer. Natural light is brought in via lightwells, glass floors or light tunnels. Ventilation and heating are designed from day one. The result is a space that feels as comfortable and bright as any room above ground.
Real projects delivered across London, Cambridge, Oxford and the Home Counties.
A clear, managed process from first conversation to final sign-off. No surprises, no delays.
Our structural engineers survey your foundation type, soil conditions and existing drainage. A full geotechnical assessment identifies any groundwater, clay or made-ground issues before work begins.
Architect and structural engineer produce working drawings. We obtain planning consent (usually required), building regulations approval and a party wall agreement with neighbours.
Underpinning, excavation, reinforced concrete walls and floors. Waterproofing system installed. This phase typically takes 10–20 weeks depending on size and ground conditions.
Lightwell or glass floor installation, MEP (mechanical, electrical, plumbing), internal partitions, flooring, decoration and any bespoke fit-out. Handover with full completion certificate.
All prices include labour, materials, project management, site clearance and building regulations. VAT and planning fees quoted separately.
Everything you need to know before you start. Still have questions? Call us for free advice.
Book a free site survey. We visit your home, assess what’s possible and deliver a fixed-price quote within 5 working days.
The narrow passage running alongside a terraced house is one of London’s most underused spaces. A side return extension reclaims it, dramatically widening your kitchen and flooding the space with daylight through a glazed roof.
For owners of Victorian and Edwardian terraced houses, the side return is often the most obvious and cost-effective way to transform the ground floor. By building into the narrow passage beside the original back addition, we can widen a kitchen from a cramped galley into a beautiful, light-filled space.
The glazed or roof-lantern ceiling over the infill area brings daylight deep into the kitchen and connecting dining area. Combined with a rear extension, the result is a completely open-plan ground floor that connects seamlessly to the garden. AQ Group handles party wall agreements, planning and all structural work in-house.
Side returns typically add 3.5–6 metres of width to the rear ground floor, transforming the cooking, dining and family living experience. We have completed side returns across London, Cambridge and Oxford — every Victorian and Edwardian terrace has one, and we know exactly how to make the most of it.
Real projects delivered across London, Cambridge, Oxford and the Home Counties.
A clear, managed process from first conversation to final sign-off. No surprises, no delays.
We assess the width of your side passage, existing foundation depth and the party wall situation. We confirm permitted development rights and advise on the best roof design for your property.
We serve party wall notices on your behalf and manage the surveyor process with your neighbour. This typically takes 4–6 weeks and rarely causes issues in our experience.
Foundations, cavity wall construction and roof structure are completed. The roof lantern or glazing is installed and the space is watertight. Existing wall opening into the kitchen is formed with steel lintel.
Flooring, plastering, electrics and plumbing are completed. New kitchen (if included) is installed and decorated. We leave a spotless, snagged and inspected space ready to enjoy.
All prices include labour, materials, project management, site clearance and building regulations. VAT and planning fees quoted separately.
Everything you need to know before you start. Still have questions? Call us for free advice.
Book a free site survey. We visit your home, assess what’s possible and deliver a fixed-price quote within 5 working days.
When a property needs everything, AQ Group delivers everything — structural alterations, complete rewiring, new plumbing, full kitchen and bathroom fit-outs and premium decoration. One team, one contract, zero headaches.
A full property renovation is one of the most satisfying projects we undertake. Whether it is a newly purchased property in need of modernisation, a dated period home requiring a sensitive update, or a complete reconfiguration of a tired family house, AQ Group has the team and the experience to deliver.
We are a full design-and-build contractor. This means our directly employed team handles every trade: structural alterations, steel installation, rewiring, replumbing, plastering, kitchen and bathroom fit-out, flooring, tiling, decoration and external works. You have one contract, one programme and one project manager who knows every detail of your job.
Full renovations we have delivered range from modest 3-bedroom terrace refreshes (£60,000–80,000) to complete gut-and-rebuild transformations of detached houses in Cambridge and Oxford (£300,000–500,000+). We provide accurate, fixed-price quotes and we stand behind them.
Real projects delivered across London, Cambridge, Oxford and the Home Counties.
A clear, managed process from first conversation to final sign-off. No surprises, no delays.
We meet, survey the property and discuss your vision, priorities and budget. We review structural drawings if available and identify any hidden issues before pricing. A detailed scope of works is agreed before any contract is signed.
Our architect and interior design partners (if needed) produce drawings and a full materials specification. We price to this specification line by line — you know exactly what every pound is spent on.
Strip-out, structural alterations, steelwork, new drainage, plumbing first fix and electrical first fix. The “blank canvas” phase — often the most dramatic transformation in the programme.
Plastering, flooring, kitchen and bathroom installations, second-fix electrics and plumbing, tiling, decoration and snagging. A full photographic record and handover pack are provided at completion.
All prices include labour, materials, project management, site clearance and building regulations. VAT and planning fees quoted separately.
Everything you need to know before you start. Still have questions? Call us for free advice.
Book a free site survey. We visit your home, assess what’s possible and deliver a fixed-price quote within 5 working days.
A beautifully designed conservatory or orangery dissolves the boundary between your home and garden. AQ Group delivers glass extensions from sleek aluminium conservatories to traditional brick orangeries with dramatic roof lanterns.
A conservatory or orangery is the most elegant way to extend your living space into the garden. Unlike a standard extension, the emphasis is on glazing — creating a light-filled room that blurs the line between indoors and outside, usable year-round with the right thermal performance.
AQ Group offers full-width aluminium conservatories with slimline profiles and maximum glass area, traditional brick pier orangeries with flat or lantern roofs, and contemporary glass box extensions that combine solid and glazed elements for a modern architectural statement. All our glazing is thermally broken, argon-filled and fitted with solar control glass.
Underfloor heating is our standard recommendation for all conservatories and orangeries — it keeps the space comfortable in winter without radiators interrupting the glass walls. We also specify self-cleaning glass for roof panels as standard, reducing maintenance to near-zero.
Real projects delivered across London, Cambridge, Oxford and the Home Counties.
A clear, managed process from first conversation to final sign-off. No surprises, no delays.
We survey the proposed location, discuss your preferred style — conservatory or orangery, aluminium or steel, flat or lantern roof — and prepare architectural drawings for planning confirmation.
Most conservatories fall under Permitted Development. We confirm PD rights or submit planning. Frame sections are factory-manufactured while foundations are prepared.
Strip foundations, dwarf walls (orangery) and frame installation. The structure is typically weathertight within 2–3 weeks of starting on site.
Roof and wall glazing installed, followed by underfloor heating, electrical works, internal finishes and decoration. Final handover with full thermal performance certification.
All prices include labour, materials, project management, site clearance and building regulations. VAT and planning fees quoted separately.
Everything you need to know before you start. Still have questions? Call us for free advice.
Book a free site survey. We visit your home, assess what’s possible and deliver a fixed-price quote within 5 working days.
A kitchen renovation by AQ Group is more than new cabinets and worktops. We manage the complete transformation — structural changes, new drainage, full electrical, plumbing and a fitted kitchen to your exact specification.
The kitchen is the most-used and most-valued room in any home. A beautifully executed kitchen renovation transforms not just the room itself, but the way your household functions every day. AQ Group takes a whole-room approach — we plan the layout, specify the units, manage structural changes and fit everything ourselves.
We work with leading kitchen suppliers — from Howdens and Wren for quality mid-range kitchens to bespoke joinery houses for fully custom cabinetry. Our in-house team handles all trades: structural alterations to walls, complete electrical rewire of the kitchen, new plumbing and drainage, floor levelling, tiling and decoration. No coordinating separate trades.
Kitchen renovations are also an ideal opportunity to combine with an extension. Many of our clients use a kitchen renovation as the fit-out phase following a rear or side return extension — a coordinated project that maximises value and minimises disruption.
Real projects delivered across London, Cambridge, Oxford and the Home Counties.
A clear, managed process from first conversation to final sign-off. No surprises, no delays.
We meet at your home, discuss the current kitchen’s shortcomings and your wishlist. We take measurements, review the existing services layout and propose a new design. You receive a design drawing with your quote.
Any wall removals, new steelwork or structural changes are completed first. New drainage routes, electrical circuits and plumbing positions are established before plastering.
Flooring preparation, wall tiling backgrounds and appliance recesses are prepared. Your kitchen units are delivered and stored safely on site.
Units, worktops, appliances, splashbacks, lighting and flooring installed. All appliances tested and commissioned. Full snagging inspection before handover.
All prices include labour, materials, project management, site clearance and building regulations. VAT and planning fees quoted separately.
Everything you need to know before you start. Still have questions? Call us for free advice.
Book a free site survey. We visit your home, assess what’s possible and deliver a fixed-price quote within 5 working days.
A bathroom renovation by AQ Group turns a functional necessity into a daily luxury. From complete en-suite installations in loft conversions to full master bathroom transformations with natural stone and heated floors — we manage every detail.
Bathroom renovation is one of the most impactful changes you can make to a home — particularly for sale or rental. AQ Group manages the complete transformation: full strip-out, waterproofing, new plumbing and waste, tiling, sanitaryware supply and installation and electrical work including underfloor heating and lighting.
We handle all types of bathroom project: refurbishing an existing bathroom in the same layout (fastest and most cost-effective), reconfiguring the layout for better use of space, converting a bedroom into a new bathroom or en-suite, and adding a luxury master bathroom suite as part of a loft conversion or full renovation.
Our bathroom projects include all necessary waterproofing (tanking to BS 5385), plumbing first and second fix, floor levelling, full wall and floor tiling, underfloor heating and all sanitaryware supply and installation. We recommend specific products based on our experience of what lasts — and what looks great for years, not just months.
Real projects delivered across London, Cambridge, Oxford and the Home Counties.
A clear, managed process from first conversation to final sign-off. No surprises, no delays.
We survey your existing bathroom, discuss the new layout and specification, and help you select sanitaryware, tiles and finishes. We provide a full materials schedule so you know exactly what you are getting before any work starts.
Full strip-out of all existing fittings. New plumbing first fix — waste and supply pipes routed to new positions. Waterproofing system applied to walls and floor in wet areas. Floor levelling compound if needed.
Wall and floor tiles laid to a setting-out plan agreed with you. Underfloor heating installed under the floor tiles. The bathroom is tiled and grouted before any sanitaryware is fitted.
All sanitaryware, shower, bath, vanity and accessories installed. Electricals connected (SELV lighting, extractor, underfloor heating thermostat). Full snagging inspection and 12-month workmanship guarantee.
All prices include labour, materials, project management, site clearance and building regulations. VAT and planning fees quoted separately.
Everything you need to know before you start. Still have questions? Call us for free advice.
Book a free site survey. We visit your home, assess what’s possible and deliver a fixed-price quote within 5 working days.
Honest advice on extensions, renovations, planning and costs — written by people who build them every day across London, Cambridge, Oxford and Herefordshire.
Get a free, no-obligation quote from London’s most trusted extension specialists.
A rear extension is the single most popular home improvement in London. But how much should you budget in 2026? We break down every cost — from groundworks to glazing — so you know exactly what to expect before you speak to a single contractor.
The honest answer: a single-storey rear extension in London costs between £1,800 and £5,000 per m² depending on your location within London, the specification you choose, and the complexity of the build. For a typical 25–35m² extension, most homeowners budget £55,000–£120,000 all in.
Five factors account for most of the variation in extension costs across London:
Labour costs in central London (Zones 1–2) run 25–35% higher than outer London (Zones 4–6). The same 30m² premium extension that costs £80,000 in Bromley might cost £108,000 in Chelsea. This isn’t just contractor markup — it reflects parking costs, congestion charges, restricted access and longer working days.
Standard: Brick or render finish, UPVC windows, laminate flooring, painted walls. Functional and solid, but no design flourishes.
Premium: Bifold or sliding doors, zinc or cladding finish, engineered timber floors, fitted kitchen, underfloor heating. This is where most London homeowners land.
Luxury: Crittall glazing, natural stone, bespoke joinery, smart home integration, designer kitchen. Prices here are genuinely open-ended.
A straightforward rear extension on a flat site with no party wall issues is the simplest and cheapest scenario. Add a sloping garden, clay soil requiring deeper foundations, a shared flank wall, or restricted access for materials, and costs climb quickly. A full structural survey before pricing is the only way to know what you are dealing with.
The ground beneath your garden determines how much the extension foundation costs. London clay is notorious for shrinkage and heave — many London properties require deeper strip foundations or even engineered solutions, adding £3,000–£15,000 to the groundworks bill. This is why no reputable contractor can give you a firm price without a site visit.
The rear wall of most modern extensions is primarily glass — bifold doors, fixed glazing panels, or a combination. Bifold doors range from £3,500 for a basic aluminium set to £18,000 for Crittall steel-framed units. A roof lantern adds £2,500–£8,000. Budget glazing significantly, because it defines the look and feel of the finished space.
A thorough, fixed-price quote from a reputable contractor should include: structural engineer calculations, architect drawings, groundworks and foundations, structural frame and roof, waterproofing, windows and rear glazing, internal plastering, electrical first and second fix, and site clearance. What it typically does not include: planning application fees (£206 as of 2026), building regulations application (£500–£900), kitchen or bathroom fit-out (quoted separately), and any decorating beyond the extension itself.
A single-storey rear extension typically adds 15–22% to a property’s value. A double-storey extension adds more space (and therefore more value), but the cost per m² is lower than single-storey because the foundations, roof and scaffolding costs are shared across two floors. In high-value London postcodes, the return on a well-executed double-storey extension almost always exceeds the build cost.
| Extension Type | Typical Size | Budget Range | Timeline |
|---|---|---|---|
| Single storey (standard) | 20–35m² | £40,000–£77,000 | 10–14 wks |
| Single storey (premium) | 20–35m² | £55,000–£112,000 | 12–16 wks |
| Double storey (premium) | 40–70m² | £100,000–£224,000 | 16–24 wks |
The only way to get an accurate price is a detailed site survey followed by a written, itemised fixed-price quote. Be wary of any contractor who quotes from photos or plans alone — they are either guessing or leaving themselves room to charge more later. AQ Group provides free site surveys across London, Cambridge, Oxford and Herefordshire, with a fixed-price quote delivered within 5 working days.
No obligation. Fixed-price quote within 5 working days. AQ Group serves London, Cambridge, Oxford and Herefordshire.
A loft conversion adds a bedroom and 20–25% to your property value without touching your garden. But which type is right for your home — and what will it actually cost in 2026?
Loft conversion costs in the UK range from £35,000 to £130,000+ depending on the conversion type, your property and your specification. The single biggest factor is which type of conversion your roof structure allows — and that determines everything else.
A Velux conversion involves no structural alterations to the roof — only the addition of roof windows (Velux being the most recognised brand), floor strengthening and a new staircase. It is the fastest, least expensive option, but it is also the most limited. You get natural light and headroom only in the centre of the space where the ridge is highest. For many properties, the usable floor area at the minimum 2.2m standing height is surprisingly small.
Best for: Properties with high ridge heights, tight budgets, or where a home office or simple guest room is the goal rather than a full master bedroom.
A dormer adds a box-shaped vertical extension to the rear slope of the roof, creating full headroom throughout the converted space. It is by far the most popular loft conversion type in London — it dramatically increases usable floor area, allows a proper en-suite bathroom, and typically falls under Permitted Development (no planning permission required).
Many semi-detached and detached homes have a “hipped” roof — where the end of the roof slopes inward rather than ending in a flat gable wall. A hip-to-gable conversion removes this slope and replaces it with a vertical gable end, creating significantly more internal space. It is usually combined with a dormer at the rear. Hip-to-gable conversions on semi-detached properties require planning permission, as they change the roofline visibly from the street.
A mansard conversion replaces the entire rear roof slope with a near-vertical wall (typically at 72 degrees) and a flat or shallow-pitched roof. It creates the maximum possible floor area from a loft conversion — often close to the footprint of the floor below. Mansard conversions always require full planning permission and are common in London conservation areas where they are sometimes the only type approved. They are also the most expensive.
| Type | Headroom | Planning Needed | Cost Range |
|---|---|---|---|
| Velux | Centre only | Usually not | £35k–£55k |
| Dormer | Throughout | Usually not | £50k–£85k |
| Hip-to-gable | Throughout | Yes | £60k–£95k |
| Mansard | Maximum | Always | £80k–£130k+ |
In London, yes — almost always. A well-designed dormer conversion adds 20–25% to a property’s value. On a £600,000 London terrace, that is £120,000–£150,000 of added value against a build cost of £55,000–£85,000. Even in slower markets and outside London, loft conversions consistently return more than their build cost.
No obligation. Fixed-price quote within 5 working days. AQ Group serves London, Cambridge, Oxford and Herefordshire.
Thousands of London homeowners apply for planning permission when they don’t need to. Thousands more assume they are covered by Permitted Development when they are not. Here is exactly how to tell the difference.
Most homeowners in England have the right to extend their home under Permitted Development (PD) rights — meaning they can build without submitting a planning application. These rights were significantly expanded by the UK government in 2020 and remain in place in 2026. Understanding them properly could save you £2,000–£5,000 in architect and planning fees, and eight weeks of waiting.
You need full planning permission for a rear extension if: your property is in a Conservation Area or is Listed; you have used up your PD rights through previous extensions; you want to exceed the PD size limits; your extension would cover more than 50% of the original garden; or your local authority has removed PD rights through an Article 4 Direction.
Large parts of inner London — and many town centres across Cambridge, Oxford and the Home Counties — are designated Conservation Areas. In these areas, Permitted Development rights are more restricted, and any extension visible from a public highway usually requires planning permission. Your local authority’s website will show whether your property is within a Conservation Area.
Some London boroughs — including parts of Islington, Hackney and Southwark — have removed Permitted Development rights in specific streets or areas via Article 4 Directions. This is worth checking at the planning pre-application stage.
For single-storey rear extensions between 4m and 8m (detached) or 3m and 6m (semi/terraced), the government introduced the Neighbour Consultation Scheme. You must notify your local authority, who consult your neighbours for 42 days. If no objections are received, the extension can proceed. This is not a planning application — it cannot be refused — but it does require a formal notification. AQ Group handles this process for all clients as part of our pre-build service.
A Lawful Development Certificate (LDC) is a formal confirmation from your local authority that your proposed or completed extension is lawful under Permitted Development rights. It costs around £100–£200 and takes 8 weeks to obtain. It is not legally required — but it is strongly recommended, particularly if you plan to sell in the next decade. Buyers’ solicitors increasingly ask for it, and without it, a sale can be delayed or fall through entirely.
A standard householder planning application takes 8 weeks from submission to decision. More complex applications, or those requiring additional consultations, can take 12–16 weeks. AQ Group submits and manages planning applications on behalf of all clients where required, typically securing approval on first submission.
No obligation. Fixed-price quote within 5 working days. AQ Group serves London, Cambridge, Oxford and Herefordshire.
That narrow alley beside your Victorian terrace is hiding one of the most cost-effective home transformations available to a London homeowner. Here is everything you need to know before you start.
A side return extension fills in the narrow passage that runs alongside the rear addition (“back addition”) of a Victorian or Edwardian terraced house. This alleyway — typically 1.5–3 metres wide — is the product of how these houses were originally designed: the main house sits forward on the plot, and a narrower rear addition houses the original kitchen and scullery. The passage beside it was left for access.
By building into this passage, you can dramatically widen the rear ground floor — transforming a dark, narrow galley kitchen into a bright, wide kitchen-diner flooded with daylight from a glazed or lantern roof above.
If your home is a Victorian or Edwardian terraced or semi-detached house built before 1914, it almost certainly has a side return. The passage runs alongside the “back addition” — the narrower rear section of the house that typically houses the original kitchen. You can identify it by looking at the plan of your house from above: the “L-shaped” footprint is the giveaway.
Because the side return runs along the boundary with your neighbour, your build will almost certainly trigger the Party Wall Act 1996. You are legally required to serve notice on any adjoining neighbours whose property shares a wall, boundary, or is within 3–6 metres of your excavation. This does not mean your neighbour can stop your extension — they cannot. But they have the right to appoint a surveyor, and if they dissent, a Party Wall Award is produced that governs how the work is carried out.
The roof of a side return infill is one of the most important design decisions you will make. A glazed or part-glazed roof — typically using structural glass or a roof lantern — transforms the space by flooding it with natural daylight. The alternative, a solid pitched or flat roof with rooflights, is less expensive but brings in less light.
We almost always recommend a glazed roof for side returns. The additional cost (£3,000–£12,000 over a solid roof) is consistently justified by the quality of the resulting space. Self-cleaning, solar-control glass keeps maintenance minimal and the space comfortable year-round.
Yes — and this is the most popular combination for London terraced houses. A “wrap-around” extension combines the side return infill with a rear extension, creating a completely open-plan ground floor that wraps around the original back addition. Doing both simultaneously is significantly more cost-effective than two separate projects, and the result — a large, light-filled kitchen-diner-living room connecting to the garden — is among the most sought-after home features in London.
No obligation. Fixed-price quote within 5 working days. AQ Group serves London, Cambridge, Oxford and Herefordshire.
The open-plan kitchen-diner is the most desired home feature in Britain. But getting it right requires more than removing a wall. Here is how to plan one that actually works — structurally, practically and beautifully.
The appeal of the open-plan kitchen-diner is obvious: more light, more space, a social cooking environment and a seamless connection to the garden. But open-plan spaces also have real drawbacks — cooking smells travel throughout the house, noise from the kitchen disrupts living areas, and the heating demands of a large volume of space are greater than two smaller rooms. Getting the balance right is a design challenge, not just a structural one.
The simplest option: remove the wall between the existing kitchen and the room behind it. Costs start at £8,000–£15,000 including structural work, making good and redecoration. The result is limited by the existing footprint — you get a bigger, lighter space but not necessarily a transformative one.
A single-storey rear extension adds a new kitchen-diner at the back of the house, typically with a glazed rear wall connecting to the garden. This is the most popular home improvement in London and for good reason: the transformation is dramatic, the ROI is proven and the build process is well-understood. Budget £55,000–£120,000 for a 25–40m² premium extension.
Filling in the side return beside a Victorian terrace widens the existing kitchen dramatically without adding a large extension. Combined with a glazed lantern roof, this creates a bright, airy kitchen that feels far larger than its square footage suggests. Ideal for homeowners who want a significant transformation without a large build programme.
Combining a side return infill with a rear extension creates a fully open-plan ground floor that wraps around the original back addition. This is the most expensive option (£90,000–£180,000) but delivers the most dramatic result: a continuous kitchen-dining-living space that opens fully to the garden.
Bifold doors fold back completely to open the full width to the garden. They create the best indoor-outdoor connection but can feel draughty if not well-specified. Budget £3,500–£12,000 depending on size and specification.
Sliding doors provide a cleaner sightline and better thermal performance than bifolds, with a more contemporary aesthetic. £4,000–£15,000.
Fixed glazing plus a door is the most affordable option and allows for the largest glass panels — maximising light while minimising cost.
Roof lanterns bring daylight into the centre of the extension — the part that fixed rear glazing can’t reach. Even a modest 1.5m x 1m lantern transforms a potentially dark extension into a light-filled room. Budget £2,500–£8,000.
The “kitchen work triangle” (the triangle between sink, fridge and hob) applies regardless of how open the space is. In a larger extension, the bigger risk is an island that is too large for the room, or a peninsula that creates a bottleneck rather than a feature. Work with a kitchen designer as part of the extension design — not as an afterthought once the walls are up.
No obligation. Fixed-price quote within 5 working days. AQ Group serves London, Cambridge, Oxford and Herefordshire.
From the first phone call to the final snagging inspection — here is exactly what to expect at every stage of a house extension, and how long each part realistically takes in 2026.
The total time from first contact with a contractor to moving back into your completed extension is typically 6–12 months for a standard rear extension. The build itself is only a fraction of this — planning, design and approvals take longer than most homeowners expect.
A thorough site survey should take 1–2 hours. The surveyor measures the existing house, assesses the ground conditions, reviews access and drainage, and discusses your brief. A detailed fixed-price quote should follow within 5 working days. If a contractor gives you a price on the phone or by WhatsApp, that is not a quote — it is a guess.
This is where most of the calendar time is spent — and it is almost entirely outside your contractor’s control. Architectural drawings take 3–6 weeks to produce. If planning permission is required, add 8 weeks for the application to be decided. Building regulations approval adds another 4–6 weeks (though this can often run concurrently with construction). Party wall notices must be served 2 months before work begins.
Single storey rear extensions take 10–14 weeks for standard builds, 12–16 weeks for premium specifications. Double storey additions take 16–24 weeks. Loft conversions take 8–14 weeks. Basements are the longest — 20–36 weeks depending on ground conditions and size.
| Extension Type | Construction Time | Total Project Time |
|---|---|---|
| Single storey rear | 10–16 weeks | 5–8 months |
| Double storey rear | 16–24 weeks | 7–12 months |
| Loft conversion | 8–14 weeks | 5–8 months |
| Basement | 20–36 weeks | 10–18 months |
| Side return | 8–14 weeks | 5–8 months |
For most rear and side return extensions, yes — with some disruption. The most difficult phase is the structural opening between the new extension and the existing house, which creates dust and noise for 2–5 days. Professional contractors dust-sheet and protect your home throughout the build, clear up at the end of every working day, and minimise disruption to utilities. Loft conversions are similarly liveable. Full renovations and basements are the exception — we generally advise decanting for these.
No obligation. Fixed-price quote within 5 working days. AQ Group serves London, Cambridge, Oxford and Herefordshire.
Basement conversions are the most complex — and often the most transformative — home improvement you can undertake. They are also expensive. Here is exactly what you get for your money, and when the numbers make sense.
A basement conversion in London costs between £2,500 and £8,000 per m², making it the most expensive form of extension per square metre. A typical 40–60m² full dig-down basement in inner London costs £120,000–£400,000 completed. The range is wide because ground conditions, access, size and specification all vary enormously.
A cellar conversion works with an existing underground space. If your property already has a cellar, the structural work is significantly simpler — you are waterproofing and fitting out an existing volume rather than creating one. Costs are £30,000–£120,000 depending on condition and specification. The main limitation is headroom: many Victorian cellars have ceiling heights of 1.8–2.0m, which can feel low. Some cellar conversions include lowering the floor to gain headroom — this adds £15,000–£40,000 to the cost.
A full dig-down involves excavating the ground beneath an existing property that has no basement. This requires underpinning — temporarily transferring the building’s load while new foundations are constructed — and is the most structurally complex type of residential construction. It is expensive, it takes time (20–36 weeks), and it requires specialist engineers and contractors.
Basement waterproofing is the single most important technical decision in any basement project, and the area where the most failures occur. There are three BS 8102-compliant waterproofing approaches: Type A (tanking — applied membranes), Type B (structural concrete) and Type C (cavity drain membrane). Most competent basement contractors use a combination of B and C. The waterproofing system should carry a minimum 10-year insured guarantee. Be extremely wary of contractors who offer shorter guarantees or proprietary systems with limited track records.
The most common objection to basement living spaces is the lack of natural light. But modern basements can be genuinely light-filled with the right design. Lightwells — excavated areas outside the basement windows — bring in daylight and can be designed as attractive garden features. Glass floors in the room above allow daylight to pass directly into the basement. Sun tubes can bring natural light from roof level down to basement rooms. AQ Group designs natural light solutions into every basement project from day one — not as an afterthought.
In prime central London (Zones 1–2), yes — a well-executed basement almost always adds more value than it costs. In inner London, the equation is closer but generally positive. In outer London and the Home Counties, the ROI on basements is less predictable and depends heavily on the local property market and the quality of the execution. The decision should always be modelled against comparable local sales before committing to a dig-down.
No obligation. Fixed-price quote within 5 working days. AQ Group serves London, Cambridge, Oxford and Herefordshire.
Most renovation disasters were predictable. The homeowner just did not ask the right questions before they handed over a deposit. Here are the ten questions that separate the good builders from the rest — and the red flags that should make you walk away.
The average cost of a disputed or abandoned building project in the UK is £20,000–£45,000 according to the FMB. Most of these disputes involve contractors who were not properly vetted before work began. Asking the right questions before signing a contract takes 30 minutes. It could save you months of stress and tens of thousands of pounds.
Any legitimate contractor carries public liability insurance — minimum £1M, ideally £5M or £10M for larger projects. If they hesitate, make excuses or cannot produce a current certificate immediately, do not hire them. Full stop. An uninsured contractor leaves you personally liable for accidents on your property.
Checkatrade, MyBuilder, the Federation of Master Builders (FMB) and TrustMark all carry out background checks and require members to meet minimum standards. Membership does not guarantee quality — but absence of any accreditation is a yellow flag. Ask to see their profile and read the reviews.
A confident, reputable contractor will give you references without hesitation. Call them. Ask specifically: did the project finish on time? Did the final cost match the quote? Were there any problems — and how were they handled? The last question is the most revealing.
These are very different things. An estimate is a guess that can change. A fixed-price quote is a legal commitment. If the quote says “estimate” or “approximate”, ask why. Legitimate contingencies should be identified and priced separately — not used as a blank cheque to charge more at the end.
Many contractors quote the job, then subcontract it out to someone cheaper and pocket the margin. Ask specifically who will be on site — their own directly employed tradespeople, or subcontractors? If subcontractors, ask who vets them and whether they are CIS registered.
A fair payment schedule is staged against progress: deposit on signing (10–20%), stages through the build tied to completed milestones, and a retention (5–10%) held until snagging is complete. Be wary of contractors who ask for large upfront payments —50% or more before any work begins is a major red flag.
Ask specifically about their guarantee on workmanship, how defects are handled, and what happens if they go out of business during the project. A reputable contractor will have clear answers. “That won’t happen” is not an answer.
Get specific dates in writing. A vague “we could probably start in a few weeks” suggests poor project management. A professional contractor works from a build programme with agreed start and completion dates, and notifies you immediately if anything changes.
Do they manage the planning and building regulations process, or do they expect you to? A full-service contractor handles submissions, liaises with inspectors and ensures all sign-offs are obtained. If they say “you need to sort the planning”, factor in the additional time and cost of an architect.
Snagging is the walk-through at the end of the project where you and the contractor identify anything that does not meet specification. Ask specifically: how long is the snagging period? When do they return to fix items? Is there a formal snagging list? Contractors who resist formal snagging processes are telling you something important.
No obligation. Fixed-price quote within 5 working days. AQ Group serves London, Cambridge, Oxford and Herefordshire.
Everything that happens before a single brick is laid — planning permission, permitted development, building regulations, architectural drawings, structural engineers and construction timelines. Your complete guide.
Permitted Dev
Planning PermissionBuilding RegsArchitecture
TimelineBefore any extension project can begin on site, a number of legal approvals must be in place. Understanding which ones apply to your project — and in which order to obtain them — saves months of delays and thousands in abortive costs.
AQ Group manages the entire pre-build process for every client: surveys, architect drawings, planning applications, building regulations, party wall notices and structural engineer sign-off. You deal with one point of contact from concept to completion.
Most homeowners can extend their home without a full planning application — but the rules are specific and the limits are firm. Understanding them properly is the first step.
When Permitted Development does not apply, a full planning application is required. The process is well-defined — and with experienced professionals managing it, approval on first submission is the norm, not the exception.
Planning permission is about whether you can build. Building regulations are about how you build — the technical standards for structure, fire safety, insulation, drainage and accessibility that every extension must meet.
The Party Wall Act protects both you and your neighbours when building work affects a shared wall, boundary or foundations near a neighbouring property. Understanding it prevents disputes and delays.
Good architectural drawings are the foundation of a successful project. They communicate your vision to the planning authority, the building inspector, the structural engineer and the construction team — preventing costly misunderstandings at every stage.
These are the drawings submitted with your planning application. They show the Local Planning Authority what you intend to build — not how you intend to build it. They include:
These are more detailed technical drawings submitted to Building Control. They show how the extension will be built to meet all regulatory requirements. They include:
Every extension requires a structural engineer. They design the load-bearing elements — foundations, steel beams, roof structure — and produce the calculations that Building Control requires before they approve the build.
From the first conversation to moving into your completed extension — here is the realistic, honest timeline for the most common project types in 2026.
From permitted development confirmation to building regulations sign-off — AQ Group manages the entire pre-build process across London, Cambridge, Oxford and Herefordshire.